Scott Pelley: Good evening from Wofford College in Spartanburg, South Carolina. I'm Scott Pelley with CBS News along with my colleague Major Garrett of National Journal. In just under a year now, Americans will go to the polls to choose a president. Tonight, CBS News and National Journal are pleased to bring you a discussion of the issues by the Republican candidates for their party's nomination.

The focus will be foreign policy and national security, the president's role as commander in chief. Consider this, the 9/11 attacks came in the eighth month of a new presidency, the Bay of Pigs in the 13th week, and the Civil War on the 40th day of a new presidency. Reminders from history that a president must be prepared to deal with a crisis from day one.

The ground rules for tonight's debate are simple. A candidate who is asked a question will have one minute to respond and then at a discretion of the moderators, there can be a 30-second follow-up or a 30-second rebuttle from another candidate. The debate will run a total of 90 minutes. The first hour will be broadcast right here on the CBS television network, the entire 90 minutes will be streamed on CBSNews.com and NationalJournal.com. And we invite you to submit questions during the debate to either w-- website. Joining me now in asking the questions, Major Garrett.

Major Garrett: Scott, thank you very much. One more piece of housekeeping. Let's introduce the candidates. Former Utah Governor, Jon Huntsman. Representing the 6th District of Minnesota, Congresswoman Michele Bachmann. Representing the 14th District of Texas, Congressman Ron Paul.

Major Garrett: This week, a U.N. nuclear watchdog agency provided additional credible evidence that Iran is pursuing a nuclear weapon. If you were president right now, what would you do specifically that this administration is not doing to prevent Iran from obtaining a nuclear weapon?

Herman Cain: The first thing that I would do is to assist the opposition movement in Iran, that's tryin' to overthrow the regime. Our enemies are not the people of Iran, it's the regime. And a regime change is what they are trying to achieve. Secondly, we need to put economic pressure on Iran, by way of our own energy independence strategy. By having our own energy independence strategy, we will impact the price of oil in the world markets, because Iran uses oil not only as a-- means of currency, but they use it as a weapon.

One of the reasons that they are able to afford that nuclear weapons program, is because of oil. Secondly, we would then work to increase sanctions on Iran, along with our friends and our allies. So whereas we will not be-- so that's why I do believe that they have a nuclear weapons program and they are closer to having nuclear weapon, stopping them-- the only we can stop them is through economic means.

Major Garrett: A quick follow up, Mr. Cain. You say assisting the opposition, would you entertain military assistance and opposition?

Herman Cain: I would not entertain-- military opposition. I'm talkin' about to help the opposition movement within the country. And then there's one other thing that we could do. We could deploy our ballistic missile defense capable (UNINTEL) war ships strategically in that part of the world. We have the biggest fleet of those warships in the world. And we could use them strategically in the event that they were able to fire a ballistic missile.

Scott Pelley: Governor Romney, would it be worth goin' to war to prevent Iran from obtaining a nuclear weapon?

Mitt Romney: Well, let's-- let's start back from there and let's talk about where we are. This is, of course, President Obama's greatest failing, from a foreign policy standpoint, which is he recognized the gravest threat that America and the world faces-- and faced was a nuclear Iran and he did not do what was necessary to get Iran to be dissuaded from their nuclear folly. What he should have done is speak out when dissidents took the streets and say, "America is with you." And work on a covert basis to encourage the dissidents.

Number two, he should have put-- put in place crippling sanctions against Iran. But instead of getting Russia, for instance, to-- what-- what he gave in our-- our missile defense system to agree to-- to stand with those crippling sanctions, he gave Russia what they wanted, their number one foreign policy objective, and got nothing in return.